Generally, the lead pin in a semiconductor package board of PGA (Pin Grid Array) type has been changing to the T type pin which is connected to the pad of the package board by soldering from the insertion type pin which is inserted into a through hole on the package board side in order to correspond intensified wiring density in recent years.
The T type pin is fixed to the electrode pad of a package board by soldering and likewise, the IC chip is also fixed to the electrode pad of the package board by soldering. The melting points of the solders for T pin connection and IC chip connection are made different from each other by changing the quantity of content of lead or their metallic composition so as to prevent the solder fixing the semiconductor loading lead pin from melting when the IC chip is connected by reflow.
The technology for enhancing the pull resistance of the T type pin has been disclosed in Prior Art 1.